The South Atlantic is one of the youngest of all the major oceans. It has prominent topographic features, in particular, the Mid-Atlantic Ridge. This feature largely determines deepwater circulation patterns that connect this ocean to the North Atlantic, Southern, Indian, and Pacific Oceans. Yet very little is known about biodiversity patterns in the South Atlantic or its connectivity with other deep areas of the world ocean. The South Atlantic MAR-ECO (SA MAR-ECO) project was developed as part of the Census of Marine Life to fill such knowledge gaps, particularly focusing on the southern Mid-Atlantic Ridge.